1. Field of the Invention
The present invention relates to the field of illumination devices, and more particularly to an uniform light emitting lamp structure that increases an angle of illumination by using a light guide column to achieve a uniform light emitting effect.
2. Description of the Related Art
In a light emitting diode (LED), a positive voltage is applied to an LED chip to emit monochromic discrete light, and the light of a desired wavelength can be emitted by the LED if the chemical composition of the LED chip is changed appropriately. In particular, after white LED was introduced, the LED is used extensively in illumination devices. With the advantages incomparable by traditional light sources, the LED is driven by a lower voltage (5V˜24V) to emit light, and thus it can achieve a power saving effect. Under an appropriate application environment or with a good heat dissipation system, the LED has a much longer using life (up to 35,000˜50,000 hours) than the traditional light sources and will not cause mercury pollutions as the traditional light sources do.
Since an LED light source is a concentrated light source with a small light emitting angle, the LED requires a special design for providing an adequate illumination angle or range. With reference to FIG. 1 for a schematic structural view of a conventional LED bulb available in the market, the LED bulb 10 comprises a lamp holder 11, an electric connection portion 111 and a planar portion 112 disposed on both end surfaces of the lamp holder 11 respectively, a circuit board 12 installed on the planar portion 112 and electrically coupled to the electric connection portion 111, an LED light source 13 arranged on the circuit board 12, and a lamp cover 14 is installed at the periphery of the planar portion 112 for covering the circuit board 12 and the LED light source 13. In general, the LED light source 13 adopts a high-power LED chip, and a large quantity of heat will be generated after the high-power LED chip is driven to emit light, so that the lamp holder 11 is usually made of a highly thermal conductive material such as aluminum in order to dissipate the heat generated by the LED light source 13 and prevent the brightness of the LED light source 13 from being affected by the heat or the life span of the LED from being shortened.
After being affected by the concentrated illumination effect of the LED light source 13 and installed at the planar portion 112, the light of the LED light source 13 will be projected in the same direction of the planar portion 112. Therefore, a general LED bulb 10 usually has the problem of a non-uniform light emission caused by an insufficient illumination angle of the LED light source 13; particularly, the brightness of lateral lights will drop significantly or even the problem of producing a showdown arises, since the light is blocked by the lamp holder 11.
In view of the shortcomings of the conventional LED bulb, the inventor of the present invention provides a lamp structure capable of achieving a uniform light emitting effect, and the lamp structure uses a light guide column and an environmental medium of different refractive indexes, and wraps and installs an LED light source into the light guide column, and the light guide column has a critical plane on an end surface, such that after the light of the LED light source is incident into the light guide column from the environmental medium, a portion of light is exited from the critical plane of the light guide column through a refraction and a reflection, and a uniform light emitting effect can be achieved when the light of the LED light source is exited from the light guide column and entered into the environmental medium.